This invention is directed to a closed thermodynamic system wherein first and second vessels have a vapor or gas phase driven engine therebetween to form a closed system. Heating and cooling of the vessels, alternately, drives the vapor engine.
The conversion of heat to mechanical power has been accomplished in a number of different ways. Quite often, a liquid is boiled to the vapor or gas phase, and the vapor is expanded in a vapor engine to a lower pressure, and thereupon, the vapor is discharged to atmosphere, or in the more efficient system, it is condensed. Usually, the condensed liquid is pumped back to the higher pressure boiler. The thermodynamic fluid serves in its liquid and gas phases as the intermediate medium for the transfer of heat and conversion to mechanical energy. A convenient intermediate fluid is water, which usually changes in state between its liquid phase and vapor or gas phase in the process. Various different sources of heat for vaporizing the water have been employed. Fossil fuels (such as oil, gas and coal) have been widely used. In order to decrease reliance on fossil fuel-fired boilers, nuclear reactions have been employed to produce the heat for producing steam, which is then used to drive turbines. Such systems are conventionally partially closed systems with a condenser having its liquid drained therefrom by a feed pump which resupplies the liquid to the boiler. Such systems are most efficient where they can be operated in large scale, but such large systems require a large supply of water, both for cooling and for circulating system makeup.
However, there is need for a closed thermodynamic system which is capable of producing mechanical power from smaller heat sources and from waste heat sources. Such systems should be completely closed and easily controllable so that minimum maintenance is required.